1. Field of the Invention
This invention relates to the preparation of rigid cellular polymer materials, particularly polyisocyanurate and polyurethane foams, characterized by improved insulating properties. More particularly, the invention relates to an improvement in the foam's insulating capacity by adding a perfluorinated hydrocarbon to the foam-forming composition.
2. Description of the Prior Art
The preparation of rigid foams characterized by isocyanurate and urethane linkages is well known in the art. Generally, these foams are prepared by reacting an organic polyisocyanate with a polyol in the presence of a blowing agent and a catalyst(s).
These rigid foams generally have good insulative properties and are thus desirable for use as insulating materials for the construction industry, refrigeration industry, and others. In order to improve insulating properties, a variety of techniques have been proposed, such as the addition of certain reactants, as in U.S. Pat. No. 4,165,414, or other additives, as in U.S. Pat. No. 4,795,763. Any such improvement in insulation value must be accompanied by the maintenance of other important foam properties, such as dimensional stability, thermal resistance and compressive strength to yield a viable candidate for commercial utilization.